Clay film

ABSTRACT

The present invention provides a clay film with excellent flexibility, whose main component is natural clay or synthetic clay, and in which there is uniform orientation in the clay particle layer, and relates to a novel clay film that has enough mechanical strength to be used as a self-supporting film, and has a structure in which layers of clay particles are highly oriented, and in which the main constituent component of the clay film is mica, vermiculite, montmorillonite, iron montmorillonite, beidellite, saponite, hectorite, stevensite, or nontronite, and which has excellent flexibility, undergoes no structural change at high temperatures of 250° C. and up to 600° C., contains no pinholes, and has a gas permeation coefficient of less than 3.2×10 −11  cm 2 s −1 cmHg −1  at room temperature for helium, hydrogen, oxygen, nitrogen, or air.

TECHNICAL FIELD

The present invention relates to a novel clay film that has enoughmechanical strength to be used as a self-supporting film (self-standingfilm), and has highly oriented layers of clay particles. The presentinvention also relates to a composite clay film, in which a functionalcomponent is uniformly distributed in the gaps between the clay filmparticles, and which has enough mechanical strength to be used as aself-supporting film, and which has highly oriented layers of clayparticles. The present invention also relates to a gas blocking materialand a protective film that have enough mechanical strength to be used asa self-supporting film, and have highly oriented layers of clayparticles.

BACKGROUND ART

Many different production processes that involve high temperatureconditions are commonly used in a wide range of chemical industryfields. The leakage of liquids and gases from the pipe joints in theseproduction lines is prevented by gaskets, welding, and so forth. Up tonow, gaskets with excellent flexibility have been made from organicpolymer materials, for example. Unfortunately, these materials do nothave high heat resistance, with the highest being about 350° C. with animide resin, so metal gaskets have to be used at higher temperatures,but a problem is that these metal gaskets are not as flexible as thosemade from organic polymer materials.

Aluminum foils and vapor deposited aluminum films do offer high gasbarrier performance, but they are not transparent. Also, since analuminum foil is a metal, it cannot be used as a sealing material to bewrapped around a threaded component. Vapor deposited silica films aretransparent and have excellent gas barrier performance, but because thematerial that serves as a base in these vapor deposited silica films isan organic compound film, once again these films cannot be used underhigh temperature conditions over 350° C. In addition to being used asgaskets, these gas blocking materials are sometimes used by beingwrapped around joint threads, wrapped around a tube, or stuck onto aflat member.

Enzymes such as glucose oxidase are generally useful as biocatalysts,have extremely high selectivity, and have the characteristic ofspecifically conducting a reaction, but a drawback is their poor heatresistance. However, it is known that the thermal stability of organicmaterials is generally quite high when they are enclosed in an inorganicmaterial. In view of this, there have been a number of attempts atimproving the thermal stability of these enzymes by enclosing them in aninorganic material, for example.

Nylon resins are widely used as molding materials because of theirexcellent strength and wear resistance, but they also have a low thermaldeformation temperature, have poor dimensional stability after absorbingmoisture, and shrink considerably in molding, among other drawbacks.Therefore, there has been research into adding clay as a filler in aneffort to raise the thermal deformation temperature, increasedimensional stability during moisture absorption, and reduce moldingshrinkage. One nylon resin composition that has been proposed contains amixture of 35 to 80 wt % nylon resin, 20 to 65 wt % of one or morefillers selected from among talc, calcium metasilicate, calcined clay,and silica, and 1 to 10 wt % glass fiber, with this mixture beingpelletized in an extruder (Japanese Laid-Open Patent ApplicationS51-7056). In this case, however, a problem is that it is difficult toblend the nylon resin with the filler and glass fiber if the nylon resinaccounts for less than 35 wt %.

A method that has been developed for manufacturing a clay mineral andnylon composite with excellent rigidity and impact resistance involvesusing a fibrous clay mineral such as sepiolite or palygorskite in aproportion of 1 to 30 weight parts (as solids) per 100 weight parts ofnylon monomer (Japanese Patent Publication H6-84435). In this case,however, a problem is that if the amount of fibrous clay mineral is over30 weight parts, there is less contact between the nylon monomerparticles, and the molecular weight of the nylon is lower. These methodswere mainly developed with an eye to enhancing the characteristics ofnylon, and the proportion of the total weight of the material accountedfor by the clay mineral is 65% or less.

Meanwhile, clay thin films have been produced up to now using theLangmuir-Blodgett method (H. Shiramizu, “Clay Mineralogy—Basics of ClayScience,” Asakura Shoten, p. 57 (1988)). However, this method involvedforming a clay thin film on the surface of a substrate made from glassor another such material, and a clay thin film that was strong enough tobe self-supporting could not be obtained. There have also been reportsof various methods for preparing functional clay thin films and thelike. For instance, there is a method for manufacturing a clay thin filmin which an aqueous dispersion of a hydrotalcite-based interlayercompound is made into a thin film and dried (Japanese Laid-Open PatentApplication H6-95290), a method for manufacturing a laminar clay mineralthin film in which the bond structure of a laminar clay mineral isoriented and fixed by performing a heat treatment that promotes areaction between the laminar clay mineral and phosphoric acid orphosphoric acid groups (Japanese Laid-Open Patent ApplicationH5-254824), and an aqueous composition for a coating treatment,containing a complex compound of a divalent or higher metal and asmectite-based clay mineral (Japanese Laid-Open Patent Application2002-30255), to name just a few of the many extant examples.Nevertheless, there are no cases of the development of a clay orientedthin film that has enough mechanical strength to be used as aself-supporting film, and in which layers of clay particles is highlyoriented.

Also, it is known that a film with uniform particle orientation can beformed by dispersing clay in water or an alcohol, spreading out thisdispersion over a glass sheet, and leaving it to dry, and orientedsamples for use in X-ray analysis have been prepared (Y. Umezawa, NendoKagaku, Vol. 42, No. 4, 218-222 (2003)). However, when a film is formedon a glass sheet, it is difficult to peel the clay film away from theglass because cracks develop in the film during peeling, for example, soit has been difficult to obtain a self-supporting film. Also, even ifthe film can be peeled off, the resulting film is brittle and lacking instrength, and there has been no method for preparing a film that isuniform in thickness and free of pinholes. Accordingly, clay thin filmshave not as yet been applied as self-supporting films.

Also, polymers that are soluble in water are used as molding materials,and are also added as a dispersant, thickener, or binder to an inorganicmaterial and used as a gas barrier material. For instance, a compositionis formed from 1 to 10 weight parts of a clay mineral or other inorganiclaminar compound and 100 weight parts of a mixture of (A) a highlyhydrogen-bondable resin containing two or more carboxyl groups permolecule and (B) a highly hydrogen-bondable resin containing two or morehydroxyl groups in its molecular chain, where the weight ratio A/B=80/20to 60/40, molding a film with a thickness of 0.1 to 50 μm from thiscomposition, and subjected this film to heat treatment and electron beamtreatment, the result of which is that this film has gas barrierproperties (Japanese Laid-Open Patent Application H10-231434). In thiscase, however, a problem is that the main component is a water-solublepolymer resin, so heat resistance is not very high.

Also, a laminated film that has excellent moisture resistance and gasbarrier property and is suited to food packaging can be obtained bylaminating a layer composed of a resin composition containing a resinand an inorganic laminar compound between two polyolefin-based resinlayers (Japanese Laid-Open Patent Application H7-251489). In this case,however, the layer of resin composition containing an inorganic laminarcompound is used as part of a multilayer film, and not alone as aself-supporting film. Also, the volumetric ratio of this resincomposition (an inorganic laminar compound/resin) is specified as beingbetween 5/95 and 90/10, with the resin contained in an amount of atleast 10%.

So far there has been no film that had enough mechanical strength to beused as a self-supporting film and in which layers of clay particleswere highly oriented. Meanwhile, in the cosmetic and pharmaceuticalfields, there have been proposals for a favorable spherical, organic,composite clay mineral (Japanese Laid-Open Patent Application S63-64913and Japanese Patent Publication H07-17371), the manufacture of a drugfor treating wet athlete's foot, comprising a mixture of a clay mineral,an acid, and an enzyme (Japanese Laid-Open Patent Application S52-15807and Japanese Patent Publication S61-03767), and so forth in which clayand an organic compound were compounded. Nevertheless, it is a fact thatthese organic composite clay minerals have yet to be used asself-supporting films, and there is an urgent need in this field oftechnology for the development and practical application of a novel claythin film having enough mechanical strength to be used as aself-supporting film.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a novel materialcomposed of an oriented clay film that has excellent flexibility underhigh temperature conditions over 350° C., and that has excellent barrierproperties against gases and liquids.

It is an object of the present invention to provide a novel compositeclay film and glucose oxidation catalyst having heat-resistant glucoseoxidation catalysis performance.

It is an object of the present invention to provide a flexible, orientedself-supporting clay film that contains a polyhydric phenol, with thispolyhydric phenol being uniformly distributed in a thin film, and thathas excellent thermal stability.

It is an object of the present invention to provide a flexible, orientedself-supporting clay film that contains nylon, with this nylon beinguniformly distributed in a thin film, and that has excellent thermalstability.

It is an object of the present invention to provide a water-solublepolymer clay film that has excellent thermal stability and is aflexible, oriented self-supporting clay film.

It is an object of the present invention to provide a strip of clay filmin many different forms.

It is an object of the present invention to provide a flexible gasblocking material in which clay is oriented and densely laminated, whichaffords enough mechanical strength to be used as a self-supporting film,optical transmissivity, and excellent thermal stability.

It is an object of the present invention to provide a novel protectivefilm composed of an oriented clay film that has excellent flexibilityunder high temperature conditions over 350° C., and which has excellentbarrier properties against gases and liquids.

The present invention which solves the above-mentioned problems will nowbe described in detail.

The present invention is a clay film made up of a main component ofclay, or clay and a small amount of additive, or clay and a small amountof additive and a functional component, having a structure in whichlayers of clay particles are highly oriented, having enough mechanicalstrength and flexibility to be used as a self-supporting film, andhaving a gas permeation coefficient of less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹.In the present invention, the main constituent component of the clayfilm is natural clay or synthetic clay, and the main constituentcomponent of the clay film is one or more components selected from thegroup comprising mica, vermiculite, montmorillonite, ironmontmorillonite, beidellite, saponite, hectorite, stevensite, andnontronite. Also, in the present invention, the additive is one or moretypes selected from the compound group comprising epsilon-caprolactam,dextrin, chitosan, starch, cellulose resin, gelatin, agar-agar, wheatflour, gluten, alkyd resin, polyurethane resin, epoxy resin,fluororesin, acrylic resin, methacrylic resin, phenol resin, polyamideresin, polyester resin, polyimide resin, polyvinyl resin, polyethyleneglycol, polyacrylamide, polyethylene oxide, protein, deoxyribonucleicacid, ribonucleic acid, polyamino acid, phenols, and benzoic acids. Theweight proportion of the additive versus the total solids is not morethan 30%.

The clay film of the present invention has any two-dimensional planarshape, such as circular, square, or rectangular, and can be used as aself-supporting film. The thickness of the clay film is less than 1 mmand the surface area is greater than 1 cm². With the clay film of thepresent invention, the flexibility is excellent, there is no structuralchange at high temperatures of over 250° C. and up to 600° C., and thereare no pinholes. The gas permeation coefficient is less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹ at room temperature for helium, hydrogen, oxygen, nitrogen,or air. The gas permeation coefficient is less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹ at room temperature for helium, hydrogen, oxygen, nitrogen,or air after 24 hours of heat treatment at 600° C. The water permeationcoefficient is not more than 2×10⁻¹⁰ cm s⁻¹ at room temperature.

This clay film is characterized in that it is a self-supporting film, isflexible, easy to work, and easy to add functions to, has a thickness of3 to 30 μm, for example, and is highly oriented, with orientation on themicrometer or nanometer order. As to the basic functions of this clayfilm, its gas barrier performance with helium is under the detectablelimit (equivalent to aluminum foil), its moisture permeability is 500g/m²/day (equivalent to cellophane), its heat resistance is 1000° C.without an additional film and 600° C. with an additional film, itstensile strength is equivalent to that of low-density polyethylene, itswater resistance is such that it will not swell when soaked in water(water-resistant), its water blocking is such that the water permeationcoefficient is 2×10⁻¹⁰ cm/sec or less, and its optical transmissivity issuch that at least 85% of visible light (500 nm) can be transmitted. Thegas permeability of this clay film is 1/5 at a clay/polymer ratio of5/95, and 1/2400 at 95/5, if we let the gas permeability be 1 at 0/100.With this clay film, particularly high gas barrier performance can beobtained by raising the proportion of the main component clay.

With the present invention, the optical transmissivity of the clay filmcan be adjusted to 85% or higher, for example, according to how muchvisible light (500 nm) transmissivity is needed.

The clay film of the present invention itself makes use of a laminarsilicate as its main raw material (90 wt % and up), and the basicstructure is preferably made up of at least 90 wt % natural orsynthetic, swellable, laminar silicate with a layer thickness ofapproximately 1 nm, a particle size up to 1 μm, and an aspect ratio ofup to about 300, and up to 10 wt % natural or synthetic, low- orhigh-molecular weight additives with a molecule size of up to a fewnanometers, for example. This clay film is produced by stacking laminarcrystals with a thickness of approximately 1 nm, with the crystalsoriented in the same direction, and densely laminating these. The clayfilm thus obtained has a thickness of 3 to 100 μm, and preferably 3 to30 μm, its gas barrier performance is such that the oxygen permeabilityat a thickness of 30 μm is less than 0.1 cc/m²·24 hr·atm, its waterpermeability is less than 0.1 cc/m²·24 hr·atm, its water blocking issuch that the water permeation coefficient is 2×10⁻¹⁰ cm/sec or less,its optical transmissivity is such that at least 75% of visible light(500 nm) is transmitted, for example, its surface area can be increasedto at least 100×40 cm, and its heat resistance is high, with no decreasein gas barrier performance is seen after 24 hours of heat treatment at600° C.

The clay film of the present invention can be easily cut with scissors,a cutter, or the like to the desired size and shape, such as circular,square, or rectangular. The clay film of the present inventionpreferably has a thickness of less than 1 mm and a surface area greaterthan 1 cm². Favorable examples of the main constituent component of theclay film include mica, vermiculite, montmorillonite, ironmontmorillonite, beidellite, saponite, hectorite, stevensite, andnontronite. Also, the clay film of the present invention ischaracterized in that the layers of clay particles are highly oriented,and there are no pinholes, and is characterized in that flexibility isexcellent and there is no structural change at high temperatures of over250° C. and up to 600° C. The clay film of the present invention is alsocharacterized in that can be used as a self-supporting film, can be usedunder high temperature conditions over 250° C., has excellentflexibility, is a solid material with no pinholes, and has excellent gasbarrier properties against gases and liquids.

With the present invention, a clay film can be obtained as aself-supporting film by preparing a uniform, dilute clay aqueousdispersion, allowing this dispersion to stand horizontally so that theclay particles gradually precipitate, separating the liquid (thedispersion medium) by any of various solid-liquid separation methods,such as centrifugation, filtration, vacuum drying, freeze vacuum drying,and heating evaporation, then forming this product into a film, andpeeling the film away from its support, and by employing manufacturingconditions here which will yield enough strength for the film to be usedas a self-supporting film of uniform thickness.

With the present invention, the clay can be either natural or syntheticsmectite, or a mixture of these, which is added to water or to a liquidwhose main component is water, so as to prepare a dilute, uniform claydispersion. The concentration of the clay dispersion is preferably from0.5 to 10 wt %, and even more preferably from 1 to 3 wt %. If theconcentration of the clay dispersion here is too low, drying will taketoo long. If the concentration of the clay dispersion is too high,though, the clay will not disperse well and a uniform film cannot beobtained. This clay dispersion is then allowed to stand horizontally sothat the clay particles gradually precipitate, and the liquid (thedispersion medium) is gradually evaporated off to form a film, forexample. In this case, a dry clay film is preferably obtained by any ofa variety of solid-liquid separation methods, favorable examples ofwhich include centrifugation, filtration, vacuum drying, freeze vacuumdrying, and heating evaporation, or a combination of these methods.

Of the above methods, when heating evaporation is used, for instance,the dispersion, which has been deaerated before being put under avacuum, is poured into a flat tray, preferably one made of plastic ormetal, and kept horizontal while it is dried for anywhere from 3 hoursto about half a day, and preferably from 3 to 5 hours, under temperatureconditions of 30 to 70° C., and preferably 40 to 50° C., in a forced-airoven, which gives a clay film. These drying conditions are set so as tobe adequate for removing the liquid by evaporation. If the temperatureis too low here, drying will take too long, but if the temperature istoo high, convection will occur and there will be a decrease in thedegree of orientation of the clay particles. If the clay film will notpeel away from the tray naturally, it is preferably dried undertemperature conditions of from 110 to 300° C., and even more preferablyfrom 110 to 200° C., to facilitate peeling and obtain a self-supportingfilm. If the temperature here is too low, peeling will be difficult, butif the temperature is too high, the film will tend to crack duringdrying. In the present invention, “highly orienting the layers of clayparticles” means stacking unit structure layers (thickness ofapproximately 1 nm) of clay particles so that the orientation of thelayer plane is uniform, and imparting a high periodicity in thedirection perpendicular to the layer plane. To obtain this orientationof the clay particles, a dilute, uniform clay dispersion is allowed tostand horizontally so that the clay particles gradually precipitate, andthe liquid (the dispersion medium) is gradually evaporated off to form afilm, for example.

The clay film of the present invention can be used as a gasket or thelike with excellent flexibility under high temperature conditions over350° C., for example, and can be utilized for preventing leaks in pipejoints along a production line, for example, in many applications in thechemical industry. Molecules of helium gas are smaller than those of anyother gas, which means that blocking helium gas is the most difficult.This clay film exhibits good gas barrier performance not only against avariety of gases, namely, air, oxygen gas, nitrogen gas, and hydrogengas, but also against helium gas. Therefore, this clay film is expectedto have gas barrier properties against all gases, including organicgases. It is also possible to mold the clay film and use it as aprotective film for a support without first peeling it from the supportsurface. This is an effective way to prevent corrosion and fouling of asupport, or to increase its heat resistance. This protective film isparticularly effective at blocking oxygen gas, so it should be effectiveat preventing the oxidation of a support, and can be used, for example,to rustproof metal structural materials or metal joint components.

With the present invention, it is possible to obtain as aself-supporting film a composite clay film in which a functionalcomponent such as glucose oxidase is uniformly dispersed in the gapsbetween the particles of a clay thin film that has enough mechanicalstrength to be used as a self-supporting film and has highly orientedlayers of clay particles.

With the present invention, it is possible to obtain as aself-supporting film a composite clay film in which a functionalcomponent such as glucose oxidase is uniformly dispersed in the gapsbetween the particles of a clay film that has highly oriented layers ofclay particles by preparing a uniform, dilute clay glucose oxidaseaqueous dispersion, allowing this dispersion to stand horizontally sothat the clay particles gradually precipitate, separating the liquid(the dispersion medium) by any of various solid-liquid separationmethods, such as centrifugation, filtration, vacuum drying, freezevacuum drying, and heating evaporation, then forming this product into afilm, and peeling the film away from its support, and by employingmanufacturing conditions here which will yield enough strength for thefilm to be used as a self-supporting film of uniform thickness.

With the present invention, the clay can be either natural or synthetic,and is preferably either natural or synthetic smectite, or a mixture ofthese, which is added to water or to a liquid whose main component iswater, so as to prepare a dilute, uniform dispersion. The concentrationof the clay dispersion is preferably from 0.5 to 10 wt %, and even morepreferably from 1 to 3 wt %. Next, glucose oxidase powder is weighed outand added to the clay dispersion to prepare a uniform dispersion ofglucose oxidase and clay. The proportion of glucose oxidase to the totalsolids is from 1 to 15%, and preferably from 5 to 10%. If the proportionof the glucose oxidase here is too low, the addition of the glucoseoxidase will have no effect, but if the proportion of glucose oxidase istoo high, the distribution of glucose oxidase and clay in the preparedfilm will not be uniform, so the effect of the addition will bediminished.

Then, this glucose oxidase clay dispersion is allowed to standhorizontally so that the clay particles gradually precipitate, and theliquid (the dispersion medium) is gradually evaporated off to form afilm, for example. In this case, a dry clay film is preferably obtainedby any of a variety of solid-liquid separation methods, favorableexamples of which include centrifugation, filtration, vacuum drying,freeze vacuum drying, and heating evaporation, or a combination of thesemethods. Of these methods, when heating evaporation is used, forinstance, the dispersion, which has been deaerated before being putunder a vacuum, is poured into a flat tray, preferably one made ofplastic or metal, and kept horizontal while it is dried for anywherefrom 3 hours to about half a day, and preferably from 3 to 5 hours,under temperature conditions of 30 to 70° C., and preferably 30 to 50°C., in a forced-air oven, which gives a clay film. If the dispersion isnot deaerated first, undesirable pores originating in bubbles will tendto form in the clay film.

The above-mentioned composite clay film of the present invention ischaracterized in that can be used as a glucose oxidation catalyst havingheat resistance, has excellent flexibility, is a solid material havingno pinholes, and has excellent barrier properties. Therefore, thecomposite clay film of the present invention can be used in a wide rangeof applications as a self-supporting film with excellent flexibilityunder high temperature conditions. For example, it can be used as aheat-resistant member with good barrier properties, such as a gasket forpipe joints in a production line in the chemical industry, or a similartype of product.

The thermal stability of the glucose oxidase in the composite clay filmof the present invention is markedly improved by the above compounding,so it is expected that this film will also find use as a heat-resistantenzyme catalyst. The significance of the glucose oxidase being presentin the gaps between the clay particles, rather than between clay layers,is that the glucose oxidase fills the gaps between the clay particlesand serves to bind the clay particles together. Accordingly, theaddition of glucose oxidase reduces cracking the composite clay film,and this yields a clay thin film having excellent characteristics thatcan be used as a self-supporting film.

The present invention provides, for example, a composite clay film inwhich a polyhydric phenol is uniformly distributed within a clay thinfilm that has enough mechanical strength to be used as a self-supportingfilm and has highly oriented layers of clay particles.

Examples of polyhydric phenols include hydroquinone, resorcinol,pyrocatechol, pyrogallol, and phloroglucin.

The significance of the polyhydric phenol being uniformly distributedwithin the clay thin film is that the polyhydric phenol molecules arechemically bonded by dehydration condensation during heating, but if thepolyhydric phenol is uniformly distributed within the clay thin film,the network of chemical bonds of the phenol can spread out more evenlywithin the clay film, so a thin film is obtained with excellent strengthand flexibility. Accordingly, the addition of the polyhydric phenolmakes it less likely that the composite clay film will be easily torn bybeing pulled, twisted, etc., and this means that the resulting compositeclay film will have excellent characteristics and can be used as aself-supporting film.

With the present invention, a composite clay film in which a polyhydricphenol is uniformly distributed in a clay thin film that has highlyoriented layers of clay particles can be obtained as a self-supportingfilm by preparing a uniform, dilute aqueous dispersion containing clayand polyhydric phenol, allowing this dispersion to stand horizontally sothat the clay particles gradually precipitate, separating the liquid(the dispersion medium) by any of various solid-liquid separationmethods, such as centrifugation, filtration, vacuum drying, freezevacuum drying, and heating evaporation, then forming this product into afilm, and peeling the film away from its support, and by employingmanufacturing conditions here which will yield enough strength for thefilm to be used as a self-supporting film of uniform thickness.

The polyhydric phenol can be a commercially available reagent, such aspyrocatechol, resorcin (resorcinol), or hydroquinone having two hydroxylgroups, or phloroglucin or pyrogallol having three hydroxyl groups.Because these have a plurality of hydroxyl groups, they readilydissolved in water, and can be uniformly dissolved in an aqueousdispersion. Also, since their evaporation pressure is low, even if theyare heated somewhat, they will not volatilize and be lost from the film.Another anticipated effect is that these will polymerize and strengthenthe laminar structure of the clay particles through a dehydrationcondensation reaction resulting from heat treatment.

With the present invention, the clay can be either natural or synthetic,and is preferably either natural or synthetic smectite, or a mixture ofthese, which is added to water or to a liquid whose main component iswater, so as to prepare a dilute, uniform dispersion. The concentrationof the clay dispersion is preferably from 0.5 to 10 wt %, and even morepreferably from 1 to 3 wt %. Next, a polyhydric phenol powder is weighedout and added to the clay dispersion to prepare a uniform dispersion ofpolyhydric phenol and clay. The proportion of polyhydric phenol to thetotal solids is from 1 to 30%, and preferably from 5 to 20%. If theproportion of the polyhydric phenol here is too low, the addition of thepolyhydric phenol will have no effect, but if the proportion ofpolyhydric phenol is too high, the distribution of polyhydric phenol andclay in the prepared film will not be uniform, so the effect of theaddition will be diminished.

The present invention also provides, for example, a composite clay filmin which nylon is uniformly distributed in a composite clay film thathas enough mechanical strength to be used as a self-supporting film andhas highly oriented layers of clay particles.

With the present invention, a composite clay film in which nylon isuniformly distributed in a clay thin film that has highly orientedlayers of clay particles can be obtained as a self-supporting film bypreparing a uniform, dilute aqueous dispersion containing clay andnylon, allowing this dispersion to stand horizontally so that the clayparticles gradually precipitate, separating the liquid (the dispersionmedium) by any of various solid-liquid separation methods, such ascentrifugation, filtration, vacuum drying, freeze vacuum drying, andheating evaporation, then forming this product into a film, and peelingthe film away from its support, and by employing manufacturingconditions here which will yield enough strength for the film to be usedas a self-supporting film of uniform thickness.

With the present invention, the clay can be either natural or synthetic,and is preferably either natural or synthetic smectite, or a mixture ofthese, which is added to water or to a liquid whose main component iswater, so as to prepare a dilute, uniform dispersion.

Next, a nylon monomer powder is weighed out and added to the claydispersion to prepare a uniform dispersion of nylon monomer and clay.The proportion of nylon to the total solids is from 1 to 30%, andpreferably from 5 to 20%. If the proportion of the nylon monomer here istoo low, the addition of the nylon monomer will have no effect, but ifthe proportion of nylon monomer is too high, the distribution of nylonmonomer and clay in the prepared film will not be uniform, so the effectof the addition will be diminished.

Then, this nylon monomer clay dispersion is allowed to standhorizontally so that the clay particles gradually precipitate, and theliquid (the dispersion medium) is gradually evaporated off to form afilm, for example. Preferably, a dry clay film is obtained by any of avariety of solid-liquid separation methods, favorable examples of whichinclude centrifugation, filtration, vacuum drying, freeze vacuum drying,and heating evaporation, or a combination of these methods. Of thesemethods, when heating evaporation is used, for instance, the dispersion,which has been deaerated before being put under a vacuum, is poured intoa flat tray, preferably one made of plastic or metal, and kepthorizontal while it is dried for anywhere from 3 hours to about half aday, and preferably from 3 to 5 hours, under temperature conditions of30 to 70° C., and preferably 30 to 50° C., in a forced-air oven, whichgives a clay film.

The above-mentioned composite clay film is subjected to a polymerizationtreatment for approximately 1 hour or longer, and preferably forapproximately 5 hours, by being heated at between 250 and 270° C., topolymerize the nylon monomer. If the temperature here is too low, thepolymerization will not progress completely, but if the temperature istoo high, the nylon will tend to deteriorate. With the presentinvention, the above steps of drying and heat treatment can be performedsimultaneously or overlapping in time so as to achieve the intendedobject.

The composite clay film of the present invention can be used in a widerange of applications as a self-supporting film with excellentflexibility under high temperature conditions. For instance, it can beused as a member with high barrier performance and heat resistance, suchas a gasket for pipe joints along a production line in the chemicalindustry, or a similar product. The significance of nylon beinguniformly distributed within the clay thin film is that the during heattreatment the nylon monomer molecules form chemical bonds through ringcleavage polymerization, but if the nylon monomer is uniformlydistributed in the clay thin film in the course of this, then thenetwork of chemical bonds of the nylon can spread out more evenly withinthe clay film, so a thin film is obtained with excellent strength andflexibility. Accordingly, the addition of the nylon monomer makes itless likely that the composite clay film will be easily torn by beingpulled, twisted, etc., and this means that the resulting clay thin filmwill have excellent characteristics and can be used as a self-supportingfilm.

The present invention also provides a water-soluble polymer compositeclay film that has enough mechanical strength to be used as aself-supporting film, and in which the clay particles are highlyoriented, and a water-soluble polymer is uniformly distributed within alaminated clay film. Examples of this water-soluble polymer include oneor more types selected from among dextrin, starch, cellulose resin,gelatin, agar-agar, wheat flour, gluten, alkyd resin, polyurethaneresin, epoxy resin, fluororesin, acrylic resin, methacrylic resin,phenol resin, polyamide resin, polyester resin, imide resin, polyvinylresin, polyethylene glycol, polyacrylamide, polyethylene oxide, protein,deoxyribonucleic acid, ribonucleic acid, and polyamino acid. The weightratio of water-soluble polymer to the total solids is 10% or less.

The water-soluble polymer used in the present invention has a polargroup on its main chain or a side chain, and is therefore hydrophilic,and while there are no particular restrictions on this polymer so longas it is soluble in water, favorable examples include one or more typesselected from among dextrin, starch, cellulose resin, gelatin,agar-agar, wheat flour, gluten, alkyd resin, polyurethane resin, epoxyresin, fluororesin, acrylic resin, methacrylic resin, phenol resin,polyamide resin, polyester resin, imide resin, polyvinyl resin,polyethylene glycol, polyacrylamide, polyethylene oxide, protein,deoxyribonucleic acid, ribonucleic acid, and polyamino acid. Thesmectite or other clay used in the present invention is alsohydrophilic, and disperses well in water. The water-soluble polymer andclay have affinity with each other, and when they are mixed in waterthey readily bond and form a compound.

The clay film of the present invention can be used as a self-supportingfilm, can be used under high temperature conditions over 350° C., hasexcellent flexibility, is a solid material that is free of pinholes, andhas excellent barrier properties. Therefore, the clay film of thepresent invention can be used in a wide range of applications as agasket or separator with excellent flexibility under high temperatureconditions over 250° C., and can be used to prevent leaks in pipe jointsalong a production line in many fields of the chemical industry, as adiaphragm in batteries and electrolysis apparatus, and so forth.

The present invention provides, for example, a gas blocking materialmade from a film whose main constituent component is clay, this gasblocking material 1) being constituted by clay alone or by clay and anadditive, 2) having a weight ratio of clay to total solids of over 90%,3) having gas barrier properties, and 4) having enough mechanicalstrength to be used as a self-supporting film.

The clay used in the present invention can be either natural orsynthetic, and is preferably one or more components selected from amongmica, vermiculite, montmorillonite, iron montmorillonite, beidellite,saponite, hectorite, stevensite, and nontronite. Even more preferably,it is either natural or synthetic smectite, or a mixture of these. Thewater-soluble polymer used in the present invention has a polar group onits main chain or a side chain, and is therefore hydrophilic, or iscationic or anionic, and while there are no particular restrictions onthis polymer so long as it is soluble in water, favorable examplesinclude one or more types selected from among epsilon-caprolactam,dextrin, starch, cellulose resin, gelatin, agar-agar, wheat flour,gluten, alkyd resin, polyurethane resin, epoxy resin, fluororesin,acrylic resin, methacrylic resin, phenol resin, polyamide resin,polyester resin, imide resin, polyvinyl resin, polyethylene glycol,polyacrylamide, polyethylene oxide, protein, glucose oxidase,peroxidase, deoxyribonucleic acid, ribonucleic acid, polyamino acid,polyhydric phenol, and 3,5-dihydroxybenzoic acid. The smectite or otherclay used in the present invention is also hydrophilic, and disperseswell in water. The water-soluble polymer and clay have affinity witheach other, and when they are mixed in water they readily bond and forma compound.

The clay film of the present invention can be used in a wide range ofapplications as a self-supporting film with excellent flexibility underhigh temperature conditions. For example, in addition to being used as agasket, it can be used by being wrapped around joint threads, wrappedaround a tube, or stuck onto a flat member.

An example of sticking the above-mentioned clay film onto a flat memberis a multilayer application. That is, a composite clay film is combinedwith a film B produced from some other material, and this multilayerstructure can be used to enhance gas barrier performance and mechanicalstrength. For example, a multilayer film can be produced by using anadhesive to stick a composite clay film together with a fluororesin film(a type of plastic film). Because a fluororesin film has low moisturepermeability, a multilayer film of a fluororesin film and a compositeclay film can be used as a film that has high moisture blockingperformance and high gas barrier performance. There are no particularrestrictions on the material of this film B, so long as the multilayerfilm with the clay film has good moldability, but favorable examplesinclude a metal foil, a thin sheet of glass, various kinds of plasticfilms, and paper. A multilayer film consisting of three or more layersand including a composite clay film can also be used.

The clay film of the present invention can be used as a self-supportingfilm, can be used under high temperature conditions over. 350° C., hasexcellent flexibility, is a solid material that is free of pinholes, andhas excellent barrier properties. Therefore, the clay film of thepresent invention can be used in a wide range of applications as acovering material, gasket, or separator with excellent flexibility underhigh temperature conditions over 350° C., and can be used to preventleaks in pipe joints along a production line in many fields of thechemical industry, as a diaphragm in batteries and electrolysisapparatus, to cover gas piping or flat members, and so forth.

The present invention provides, for example, a protective film made ofan oriented clay film whose main raw material is clay, with thisprotective film 1) containing 90 to 100 wt % clay with respect to thetotal solids content, 2) having gas barrier properties, and 3) havingenough mechanical strength to be used as a self-supporting film.

With the present invention, an oriented clay film in which layers ofclay particles are highly oriented and which has enough mechanicalstrength to be used as a self-supporting film can be obtained as aprotective film self by preparing a uniform, dilute clay aqueousdispersion, allowing this dispersion to stand horizontally so that theclay particles gradually precipitate on the surface of a support,separating the liquid (the dispersion medium) by any of varioussolid-liquid separation methods, such as centrifugation, filtration,vacuum drying, freeze vacuum drying, and heating evaporation, thenforming this product into a film, and peeling the film away from itssupport, and by employing manufacturing conditions here which will yieldenough strength for the film to be used as a self-supporting film ofuniform thickness.

A protective film composed of the oriented clay film of the presentinvention can be used, for example, as a protective film with excellentheat resistance under high temperature conditions over 350° C., and canbe used to prevent oxidation, improve heat resistance, and so forth in avariety of members in many different industrial fields. Molecules ofhelium gas are smaller than those of any other gas, which means thatblocking helium gas is the most difficult. A protective film composed ofthe oriented clay film of the present invention exhibits good gasbarrier performance not only against a variety of gases, namely, air,oxygen gas, nitrogen gas, and hydrogen gas, but also against helium gas.Therefore, a protective film composed of the oriented clay film of thepresent invention is expected to have gas barrier properties against allgases, including organic gases. It is also possible to mold the orientedclay film and use it as a protective film for a support without firstpeeling it from the support surface. This is an effective way to preventcorrosion and fouling of a support, or to increase its heat resistance.This protective film is particularly effective at blocking oxygen gas,so it should be effective at preventing the oxidation of a support, andcan be used, for example, to rustproof metal structural materials ormetal joint components.

With the present invention, an additive such as a thickener can beadded, or the solid-liquid ratio can be raised above that of aconventional clay dispersion, to obtain a clay paste with lower fluidityand high viscosity than those of the clay dispersion. Using a clay pastecan shorten the drying time over that with a conventional synthesismethod, and since the fluidity of a clay paste is lower, the coatingfilm will not run out, so there is no need for the coated object to bein the form of a divided container. Furthermore, since a clay paste hasa lower fluidity, it can be applied not only to a flat surface, but alsoto an inclined surface, among various other advantages.

The solid-liquid ratio of the clay paste used in the present inventionis from 2 to 15 wt %, and preferably 4 to 7 wt %. Because a clay pasteis thicker than a conventional aqueous dispersion, it dries faster.Whereas drying used to take about 5 hours with a conventionalmanufacturing method, the paste can be dried in about 20 minutes byadjusting the solid-liquid ratio of the clay paste to about 6%, forexample. The following two methods are examples of how a clay paste canbe prepared. In the first method, clay is dispersed in a dispersionmedium by shaking, and the dispersion medium is slowly evaporated offunder mild drying conditions (such as 50° C.) to raise the solid-liquidratio to the desired value. In the second method, clay particles and adispersion medium of a set solid-liquid ratio are directly kneaded.

Examples of dispersion media include water, either alone or togetherwith a small amount of additive as needed; specifically, an additivesuch as an organic medium or salt can be added. The purposes of addingan additive include varying the dispersibility of the paste, varying theviscosity of the clay paste, varying the ease of drying of the clayfilm, and increasing the uniformity of the clay film. Examples ofadditives include acetamide and ethanol.

There are no particular restrictions on how an object is coated with theclay paste in the method for manufacturing the clay film of the presentinvention, so long as uniform coating is possible, but one favorablemethod is to use a blade, brush, nozzle, or other such tool so as toprevent air bubbles from being admixed. Because a clay paste has a highviscosity, it can be used to coat not only a horizontal surface, butalso an inclined surface or a vertical surface. Accordingly, it ispossible to produce a clay film not only when the object to be coated isa flat surface, but even when it has some other surface shape. There areno particular restrictions on the shape so long as the paste can beuniformly applied, but clay films of complex shapes that could not beproduced with a conventional method can be produced by coating the inneror outer surface of an object whose shape is cubic, cuboid, tubular,cylindrical, conical, spherical, or a combination of these, then dryingand peeling off the coating. When an inclined surface is coated with aclay paste,.it is important to use a clay paste with high viscosity andlow fluidity to maintain a uniform coating film.

The coating thickness of the clay paste is from 0.03 to 10 mm, andpreferably 0.1 to 1 mm. If the coating is too thin, the clay film thatis produced will also be too thin, and may not have adequate mechanicalstrength. If it is too thick, however, it will take a long time to dry.The clay film of the present invention can be obtained in the desiredthickness by adjusting the solid-liquid ratio or the thickness in whichthe clay paste is applied.

There are no particular restrictions on the material of the object to becoated, but it preferably has adequate heat resistance, does not readilydeform, has high thermal conductivity, and allows the clay to be peeledaway easily. Examples include stainless steel, aluminum, and copper.

In the method for manufacturing the clay film of the present invention,the manufacturing steps, namely, the clay paste preparation, clay pastecoating, drying, and peeling, can be carried out continuously is aserial process, which means that a clay film in the form of a long stripthat could not be produced up to now can be obtained, and at the sametime this increases production speed and production efficiency. It isalso possible to automate the peeling of the clay film from the coatedsubstance, and the winding of the clay film into a roll, and thisfurther increases production efficiency.

The present invention provides an oriented clay film with uniformorientation of the clay particles. The present invention also providesthe manufacture of a film that has enough mechanical strength to be usedas a self-supporting film and in which the layers of clay particles arehighly oriented. This thin film has excellent flexibility even at hightemperatures over 350° C., has high thermal stability and good barrierproperties, and can be used as a chemically table gasket, electrolytediaphragm material, or the like. The present invention also provides aglucose oxidase composite clay film in which glucose oxidase isuniformly distributed in the gaps between clay particles and the clayparticles are uniformly oriented. The present invention also provides apolyhydric phenol composite clay film in which a polyhydric phenol isuniformly distributed in the gaps between clay particles and the clayparticles are uniformly oriented. The present invention also provides anylon composite clay film in which nylon is uniformly distributed in thegaps between clay particles and the clay particles are uniformlyoriented. The present invention also provides a water-soluble polymercomposite clay film in which the clay particles are uniformly oriented.The present invention also provides a clay film in which the clayparticles are uniformly oriented. The present invention also provides aprotective film composed of an oriented clay film in which the clayparticles are uniformly oriented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a scanning electron micrograph of a Kunipia P clay thin film;

FIG. 2 is an X-ray diffraction chart of a Kunipia P clay thin film;

FIG. 3 is a TG-DTA chart of a magnesium Kunipia P powder (temperatureelevation rate: 5° C./minute, under an argon atmosphere);

FIG. 4 is a TG-DTA chart of a magnesium Kunipia P thin film (temperatureelevation rate: 5° C./minute, under an argon atmosphere);

FIG. 5 is a scanning electron micrograph of a glucose oxidase Kunipia Pthin film;

FIG. 6 is an X-ray diffraction chart of a glucose oxidase Kunipia P thinfilm;

FIG. 7 is a TG-DTA chart of a glucose oxidase Kunipia P thin film(temperature elevation rate: 5° C./minute, under an argon atmosphere);

FIG. 8 is an X-ray diffraction chart of a polyhydric phenol compositeclay thin film (resorcinol Kunipia P thin film);

FIG. 9 is a TG-DTA chart of a polyhydric phenol composite clay thin film(resorcinol Kunipia P thin film) (temperature elevation rate: 5°C./minute, under an argon atmosphere);

FIG. 10 is a TG-DTA chart of a montmorillonite (Kunipia P) powder(temperature elevation rate: 5° C./minute, under an argon atmosphere);

FIG. 11 is a TG-DTA chart of a polyhydric phenol (resorcinol)(temperature elevation rate: 5° C./minute, under an argon atmosphere);

FIG. 12 is a TG-DTA chart of a polyhydric phenol composite clay thinfilm (phloroglucin Kunipia P thin film) (temperature elevation rate: 5°C./minute, under an argon atmosphere);

FIG. 13 is a TG-DTA chart of a polyhydric phenol (phloroglucin)(temperature elevation rate: 5° C./minute, under an argon atmosphere);

FIG. 14 is an X-ray diffraction chart of a nylon composite clay thinfilm;

FIG. 15 is a TG-DTA chart of a nylon composite clay thin film(temperature elevation rate:. 5° C./minute, under an argon atmosphere);

FIG. 16 is a TG-DTA chart of a nylon yarn (temperature elevation rate:5° C./minute, under an argon atmosphere);

FIG. 17 is an X-ray diffraction chart of a nylon composite clay thinfilm when the added amount of epsilon-caprolactam is varied;

FIG. 18 is an X-ray diffraction chart of the composite clay thin film ofthe present invention prepared using a polyacrylate (weight ratio ofsodium polyacrylate used here to the total solids: 0.02%);

FIG. 19 is a TG-DTA chart of the composite clay thin film of the presentinvention prepared using a polyacrylate (weight ratio of sodiumpolyacrylate used here to the total solids: 0.02%) (temperatureelevation rate: 5° C./minute, under an argon atmosphere);

FIG. 20 is an X-ray diffraction chart of the composite clay thin film ofthe present invention prepared using a polyacrylate (weight ratio ofsodium polyacrylate used here to the total solids: 0.02%);

FIG. 21 is a TG-DTA chart of the composite clay thin film of the presentinvention prepared using a polyacrylate (weight ratio of sodiumpolyacrylate used here to the total solids: 0.02%) (temperatureelevation rate: 5° C./minute, under an argon atmosphere);

FIG. 22 is a side view of the structure of an autoclave;

FIG. 23 is a graph of how the proportion of water remaining in anautoclave that was put in an electric furnace held at 300° C., changedover time versus the initial amount when a threaded component was andwas not sealed with a composite clay film;

FIG. 24 is a diagram of the cross sectional structure of a multilayerfilm;

FIG. 25 is a diagram of the cross sectional structure of a multilayerfilm;

FIG. 26 is a scanning electron micrograph of a Kunipia P clay thin film;and

FIG. 27 is an X-ray diffraction chart of a Kunipia P clay thin film.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described in specific terms on thebasis of examples, but the present invention is not limited in any wayby these examples.

EXAMPLE 1

60 cc of distilled water was added to 1.0 g of Kunipia P (as the clay; anatural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. This clay dispersion waspoured into a flat-bottomed polypropylene tray that had a square bottommeasuring about 10 cm on each side, and the clay dispersion was allowedto stand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave asemi-transparent clay thin film with a thickness of approximately 40 μm.

FIG. 1 shows a scanning electron micrograph of this clay thin film. Itcan be seen in FIG. 1 that the layers of clay particles are highlyoriented. FIG. 2 is an X-ray diffraction chart of this clay thin film. Aseries of sharp back reflection peaks (001), (002), (003), (004), and(005) are seen at positions of 1.24, 0.62, 0.42, 0.31, and 0.21 nm,respectively, indicating that the orientation of the particles in theclay thin film is very uniform. The water permeation coefficient of thisclay film was also measured for the purpose of confirming its barrierperformance. The water permeation coefficient was measured by the methodset forth in JIS A 1218 “Method for Testing Water Permeation of Soil,”and the water permeation coefficient of this clay thin film (sodiumKunipia film) was found to be 1×10⁻¹¹ cm/sec. This value matches wellthe value of the water permeation coefficient of montmorillonite foundby molecular dynamics method (Ichikawa et al., Nihon GenshiryokuGakkai-shi, 41, 12-21 (1999)), confirming that there were no pinholes orthe like.

EXAMPLE 2

60 cc of distilled water was added to magnesium Kunipia P (as the clay),obtained by exchanging the exchangeable ions of 1.0 g of Kunipia P (anatural montmorillonite made by Kunimine Industries) with magnesium, andthis was put into a sealed plastic vessel along with a Teflon® agitatorand shaken vigorously, which gave a clay dispersion. This claydispersion was poured into a flat-bottomed polypropylene tray that had asquare bottom measuring about 10 cm on each side, and the claydispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the tray held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent clay thin film with a thickness ofapproximately 70 μm.

The clay thin film thus produced was dried in an oven held at 110° C.,which allowed the film to be easily peeled from the tray. The waterpermeation coefficient of this clay thin film (magnesium Kunipia P) wasmeasured and found to be 2×10⁻¹⁰ cm/sec. FIG. 3 is a TG-DTA chart ofmagnesium Kunipia powder. Weight loss was seen to accompany dehydrationup to 200° C., and weight loss was also caused by removal of structuralhydroxyl groups near 600° C. (H. Shiramizu, “Clay Mineralogy—Basics ofClay Science,” Asakura Shoten, p. 96-98 (1988)). Meanwhile, in a TG-DTAchart of a magnesium Kunipia film prepared using magnesium Kunipiapowder (FIG. 4), the weight loss caused by the removal of structuralhydroxyl groups near 600° C. shifted to the high temperature side, andit can be seen that the weight loss width is narrower. The reason forthis is believed to be that the film is packed with no gaps, which makesit less likely that the removal of structural hydroxyl groups will causestructural changes. This result also indicates that the clay thin filmhas high thermal stability at temperatures of 250° C. or higher.

EXAMPLE 3

60 cc of distilled water was added to 1.0 g of Smectone (as the clay; asynthetic saponite made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. This clay dispersion waspoured into a flat-bottomed polypropylene tray that had a square bottommeasuring about 10 cm on each side, and the clay dispersion was allowedto stand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave asemi-transparent clay thin film with a thickness of approximately 70 μm.The clay thin film thus produced was dried in an oven held at 110° C.,which allowed the film to be easily peeled from the tray. The waterpermeation coefficient of this clay thin film was measured and found tobe 2×10⁻¹⁰ cm/sec, and high water blocking was exhibited.

EXAMPLE 4

60 cc of distilled water was added to 1.0 g of Kunipia P (as the clay; anatural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. This clay dispersion waspoured into a flat-bottomed brass tray that had a circular bottommeasuring about 15 cm in diameter, and the clay dispersion was allowedto stand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave asemi-transparent, circular clay thin film with a thickness ofapproximately 70 μm. The clay thin film thus produced was dried in anoven held at 110° C., which allowed the film to be easily peeled fromthe tray.

The helium, hydrogen, oxygen, nitrogen, and air permeation coefficientsof this film were measured with a Gasperm-100 made by JASCO. The gaspermeation coefficients for helium, hydrogen, oxygen, nitrogen, and airat room temperature were confirmed to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance. Even after this composite thin film was heated for 24 hoursat 1000° C., the gas permeation coefficients of the composite thin filmfor helium, hydrogen, oxygen, nitrogen, and air at room temperature wereconfirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us thatthe film exhibits gas barrier performance even after high-temperaturetreatment. The optical transmissivity of this film was measured with aU-3310 absorptiometer made by Hitachi. The optical transmissivity wasmeasured by immersing the film in ethanol in a quartz rectangular celland using light with a wavelength of 500 nm. As a result, the opticaltransmissivity was found to be 75%.

EXAMPLE 5

60 cc of distilled water was added to 0.95 g of Smectone (as the clay; asynthetic saponite made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. This dispersion was pouredinto a flat-bottomed brass tray that had a circular bottom measuringabout 15 cm in diameter, and the dispersion was allowed to standhorizontally so that the clay particles would gradually settle. With thetray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave asemi-transparent, circular clay thin film with a thickness ofapproximately 30 μm. Observation by electron microscope revealed thatthe metal sheet and the clay thin film interfaces were in contact, withno gap in between, so the film did not peel away when merely touched byhand.

EXAMPLE 6

60 cc of distilled water was added to 0.95 g of Kunipia P (as the clay;a natural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.05 g of glucose oxidase powder (made by Tokyo Kasei Kogyo), andthis dispersion was poured into a flat-bottomed polypropylene tray thathad a square bottom measuring about 10 cm on each side, and the claydispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the tray held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent clay thin film with a thickness ofapproximately 40 μm.

FIG. 5 is a scanning electron micrograph of this clay thin film. It canbe seen from FIG. 5 that glucose oxidase is uniformly distributed in thegaps between clay particles, in which the layers of clay particles arehighly oriented. FIG. 6 is an X-ray diffraction chart of this clay thinfilm. Back reflection peaks 001, 002, 004, and 005 are seen at positionsof 1.28, 0.62, 0.31, and 0.21 nm, respectively, indicating that theorientation of the particles in the clay thin film is very uniform.Because these positions correspond well to the 1.24, 0.62, 0.31, and0.21 nm that are the positions of the back reflection peaks 001, 002,004, and 005 of a clay thin film containing no glucose oxidase, we cansee that the glucose oxidase is present in the gaps between the clayparticles, and not between the smectite clay layers.

Next, the water permeation coefficient of this clay thin film wasmeasured to confirm its barrier performance. A glucose oxidase Kunipia Pthin film was used as the sample. The ratio of the weight of the glucoseoxidase in this film to the combined weight of clay and glucose oxidasewas 5%. The water permeation coefficient was measured by the method setforth in JIS A 1218 “Method for Testing Water Permeation of Soil,” andfound to be 1×10⁻⁹ m/sec. Since the water permeation coefficient issufficiently small, this confirms that no pinholes or the like werepresent. FIG. 7 is a TG-DTA chart of a glucose oxidase Kunipia P thinfilm. Weight loss accompanying dehydration from room temperature up to200° C., and weight loss of 2.4% caused by decomposition of the glucoseoxidase above 200° C. were observed. Also observed were the breakdown ofthe structure of the clay mineral near 750° C., and weight lossaccompanying atomic realignment and recrystallization.

EXAMPLE 7

60 cc of distilled water was added to 0.85 g of Kunipia P (as the clay;a natural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.15 g of glucose oxidase powder (made by Tokyo Kasei Kogyo), andthis dispersion was poured into a flat-bottomed polypropylene tray thathad a square bottom measuring about 10 cm on each side, and the claydispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the tray held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent clay thin film with a thickness ofapproximately 40 μm.

EXAMPLE 8

60 cc of distilled water was added to 0.95 g of Smectone (as the clay; asynthetic saponite made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.05 g of glucose oxidase powder (made by Tokyo Kasei Kogyo), andthis dispersion was poured into a flat-bottomed polypropylene tray thathad a square bottom measuring about 10 cm on each side, and the claydispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the tray held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent clay thin film with a thickness ofapproximately 40 μm.

EXAMPLE 9

60 cc of distilled water was added to 0.85 g of Kunipia P (as the clay;a natural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.15 g of glucose oxidase powder (made by Tokyo Kasei Kogyo), andthis dispersion was poured into a flat-bottomed brass tray that had acircular bottom measuring about 15 cm in diameter, and the claydispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the tray held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent, circular clay thin film with a thicknessof approximately 30 μm. The clay thin film thus produced was dried in anoven held at 110° C., which allowed the film to be easily peeled fromthe tray.

The helium, hydrogen, oxygen, nitrogen, and air permeation coefficientsof this film were measured with a Gasperm-100 made by JASCO. The gaspermeation coefficients for helium, hydrogen, oxygen, nitrogen, and airat room temperature were confirmed to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance. Even after this composite thin film was heated for 24 hoursat 500° C., the gas permeation coefficients of the composite thin filmfor helium, hydrogen, oxygen, nitrogen, and air at room temperature wereconfirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us thatthe film exhibits gas barrier performance even after high-temperaturetreatment. The optical transmissivity of this film was measured with aU-3310 absorptiometer made by Hitachi. The optical transmissivity wasmeasured by immersing the film in ethanol in a quartz rectangular celland using light with a wavelength of 500 nm. As a result, the opticaltransmissivity was found to be 56%.

EXAMPLE 10

60 cc of distilled water was added to 0.95 g of Smectone (as the clay; asynthetic saponite made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.05 g of glucose oxidase powder (made by Tokyo Kasei Kogyo), andthis dispersion was poured into a flat-bottomed brass tray that had acircular bottom measuring about 15 cm in diameter, and the dispersionwas allowed to stand horizontally so that the clay particles wouldgradually settle. With the tray held horizontal, the dispersion wasdried for 5 hours at a temperature of 50° C. in a forced air oven, whichgave a semi-transparent, circular clay thin film with a thickness ofapproximately 30 μm. Observation by electron microscope revealed thatthe metal sheet and the clay thin film interfaces were in contact, withno gap in between, so the film did not peel away when merely touched byhand.

EXAMPLE 11

60 cc of distilled water was added to 0.70 g of Kunipia P (as the clay;a natural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.30 g of resorcinol powder (as a polyhydric phenol; made by WakoPure Chemical Industries), and this dispersion was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform polyhydric phenolcomposite clay thin film with a thickness of approximately 30 μm. Theclay thin film thus produced was dried in an oven held at 110° C. Thisgave a clay thin film that could be easily peeled from the tray. Thisfilm was then heated for 12 hours at 300° C. in an air atmosphere, whichgave a heat-treated clay thin film.

FIG. 8 is an X-ray diffraction chart of this clay thin film. The filmwas observed at the position where the back reflection peak 001 wasd=1.41 nm. This is spread out more than the value of 1.24 nm for a claythin film (Kunipia P thin film), and corresponds to a structure in whichresorcinol is incorporated between layers of montmorillonite (KunipiaP). It can be seen from these results that resorcinol is present betweenlayers of montmorillonite (Kunipia P), and is included in the claylayers. FIG. 9 is a TG-DTA chart of a polyhydric phenol composite claythin film (resorcinol Kunipia P thin film). The TG curve shows areduction in weight caused by the dehydration of adsorbed water fromroom temperature up to 200° C. A large weight reduction was observedfrom 750 to 800° C. FIG. 10 is a TG-DTA chart of montmorillonite(Kunipia P) powder. Weight loss was seen to accompany dehydration up to200° C., and weight loss was also caused by removal of structuralhydroxyl groups near 600° C. (H. Shiramizu, “Clay Mineralogy—Basics ofClay Science,” Asakura Shoten, p. 96-98 (1988)).

A comparison of the TG-DTA charts for the polyhydric phenol compositeclay thin film (resorcinol Kunipia P thin film) and the montmorillonite(Kunipia P) powder reveals that forming a film along with resorcinolshifts the removal of structural hydroxyl groups in the montmorillonite(Kunipia P) toward the high temperature side, thereby increasing heatresistance. Peaks corresponding to the melting and boiling of resorcinolwere observed at 111° C. and 208° C., respectively, on the DTA curve inthe TG-DTA charts for montmorillonite (Kunipia P) (FIG. 10) and forresorcinol (polyhydric phenol; FIG. 11). This phase change in resorcinolis not observed in the DTA curve of the TG-DTA chart for the polyhydricphenol composite clay thin film (resorcinol Kunipia P thin film). Thistells us that resorcinol is uniformly distributed on the molecular levelin the clay thin film (Kunipia P thin film), and is stabilized.

The helium, hydrogen, oxygen, nitrogen, and air permeation coefficientsof this film were measured with a Gasperm-100 made by JASCO. The gaspermeation coefficients for helium, hydrogen, oxygen, nitrogen, and airat room temperature were confirmed to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance. Even after this composite thin film was heated for 24 hoursat 500° C., the gas permeation coefficients of the composite thin filmfor helium, hydrogen, oxygen, nitrogen, and air at room temperature wereconfirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us thatthe film exhibits gas barrier performance even after high-temperaturetreatment.

EXAMPLE 12

60 cc of distilled water was added to 0.70 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.30 g of resorcinol powder (as a polyhydric phenol; made by WakoPure Chemical Industries), and this dispersion was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform polyhydric phenolcomposite clay thin film (phloroglucin Kunipia P thin film) with athickness of approximately 30 μm. The clay thin film thus produced wasdried in an oven held at 110° C. This gave a clay thin film that couldbe easily peeled from the tray.

FIG. 12 is a TG-DTA chart of the above-mentioned polyhydric phenolcomposite clay thin film (phloroglucin Kunipia P thin film). The TGcurve shows a reduction in weight caused by the dehydration of adsorbedwater from room temperature up to 200° C. A large weight reduction wasobserved from 600 to 750° C. FIG. 13 is a TG-DTA chart of phloroglucin(polyhydric phenol). The TG curve shows a large reduction in weightaccompanying dehydration condensation from 200° C. to over 300° C., andthe dehydration peak at not more than 100° C. It can be seen from theDTA curve that with phloroglucin alone, a dehydration condensationreaction proceeded after melting at 217° C. The change observed withphloroglucin alone was not observed in the DTA curve of the TG-DTA chartof the polyhydric phenol composite clay thin film (phloroglucin KunipiaP thin film). This tells us that phloroglucin is uniformly distributedon the molecular level in the clay thin film (Kunipia P thin film), andis stabilized.

EXAMPLE 13

60 cc of distilled water was added to 0.70 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.30 g of resorcinol powder (as a polyhydric phenol; made by WakoPure Chemical Industries), and this dispersion was poured into aflat-bottomed polypropylene tray that had a square bottom measuringabout 10 cm on each side, and the dispersion was allowed to standhorizontally so that the clay particles would gradually settle. With thetray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave asemi-transparent, circular polyhydric phenol composite clay thin filmwith a thickness of approximately 30 μm.

Comparative Example 1

60 cc of distilled water was added to 0.70 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.30 g of resorcinol powder (as a polyhydric phenol; made by WakoPure Chemical Industries), and this dispersion was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform polyhydric phenolcomposite clay thin film with a thickness of approximately 30 μm. Theclay thin film thus produced was dried in an oven held at 110° C. Thisgave a clay thin film that could be easily peeled from the tray. Whenthis film was immersed in distilled water, it swelled and then fellapart a few dozen minutes later, which means that it could not be keptin the form of a self-supporting film.

EXAMPLE 14

60 cc of distilled water was added to 0.70 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.30 g of resorcinol powder (as a polyhydric phenol; made by WakoPure Chemical Industries), and this dispersion was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform polyhydric phenolcomposite clay thin film with a thickness of approximately 30 μm. Theclay thin film thus produced was dried in an oven held at 110° C. Thisgave a clay thin film that could be easily peeled from the tray. Thisfilm was then heated for 12 hours at 300° C. in an air atmosphere, whichgave a heat-treated clay thin film.

This heat-treated clay thin film did not swell even after. being soakedfor 10 days in distilled water, and could be used as a self-supportingfilm. The helium, hydrogen, oxygen, nitrogen, and air permeationcoefficients of this film were confirmed to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance even after being soaked in distilled water.

EXAMPLE 15

60 cc of distilled water was added to 0.95 g of synthetic saponite (asthe clay; Smectone, made by Kunimine Industries), and this was put intoa sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.05 g of resorcinol powder (made by Wako Pure ChemicalIndustries), and this dispersion was poured into a flat-bottomed brasstray that had a circular bottom measuring about 15 cm in diameter, andthe dispersion was allowed to stand horizontally so that the clayparticles would gradually settle. With the tray held horizontal, thedispersion was dried for 5 hours at a temperature of 50° C. in a forcedair oven, which gave a semi-transparent, circular clay thin film with athickness of approximately 30 μm. Observation by electron microscoperevealed that the metal sheet and the clay thin film interfaces were incontact, with no gap in between, so the film did not peel away whenmerely touched by hand.

EXAMPLE 16

60 cc of distilled water was added to 0.95 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.05 g of epsilon-caprolactam powder (as a nylon monomer; made byWako Pure Chemical Industries), and this dispersion was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform nylon monomer compositeclay thin film with a thickness of approximately 30 μm. The clay thinfilm thus produced was peeled from the tray and heat treated for 5 hoursin a heating oven held at 250° C., which gave a nylon composite clayfilm.

FIG. 14 is an X-ray diffraction chart of the nylon monomer compositeclay film before heat treatment and the nylon composite clay film afterheat treatment at 250° C. The back reflection peaks 001 before and afterthis heat treatment were observed at positions of d1.44 nm and 1.41 nm,respectively. These were spread out more than the 1.24 nm value of aclay thin film (Kunipia P thin film), and respectively correspond tostructures in which a nylon monomer and nylon are incorporated betweenlayers of montmorillonite (Kunipia P). These results tell us that thenylon monomer and nylon are present between layers of montmorillonite(Kunipia P), and are included in the clay layers. FIG. 15 is a TG-DTAchart of a nylon composite clay thin film. The TG curve shows areduction in weight caused by the dehydration of adsorbed water fromroom temperature up to 200° C. A very slight weight reduction wasobserved near 400° C. A large weight reduction in montmorillonite wasobserved from 700 to 800° C.

FIG. 16 is a TG-DTA chart of a commercially available nylon yarn. A peakcorresponding to the decomposition of nylon is seen near 400° C. on theDTA curve. This tells us that the weight reduction of the nyloncomposite clay thin film near 400° C. in FIG. 15 accompanies thedecomposition of nylon, and this indicates that the nylon monomer ispolymerized within the composite clay film. The air permeationcoefficient of the nylon composite clay film (the weight ratio of nylonmonomer to total solids was 10%) was measured with a Gasperm-100 made byJASCO and confirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, at roomtemperature, which tells us that the film exhibits gas barrierperformance. The air permeation coefficient of the film after heattreatment for 24 hours at 500° C. was confirmed to be less than3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, at room temperature, which tells us that thefilm exhibits gas barrier performance even after high-temperaturetreatment. The optical transmissivity of this film was measured with aU-3310 absorptiometer made by Hitachi. The optical transmissivity wasmeasured by immersing the film in ethanol in a quartz rectangular celland using light with a wavelength of 500 nm. As a result, the opticaltransmissivity was found to be 88%.

EXAMPLE 17

60 cc of distilled water was added to natural montmorillonite (as theclay; Kunipia P, made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon ® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded epsilon-caprolactam powder (as a nylon monomer; made by Wako PureChemical Industries) to prepare a uniform dispersion. The weight ratioof the natural montmorillonite to the epsilon-caprolactam here was 0.90g/0.10 g (10% caprolactam), 0.80 g/0.20 g (20% caprolactam), and 0.70g/0.30 g (30% caprolactam). This dispersion was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform nylon monomer compositeclay thin film with a thickness of approximately 30 μm. The clay thinfilm thus produced was peeled from the tray and heat treated for 5 hoursin a heating oven held at 250° C.

FIG. 17 is an X-ray diffraction chart of the nylon composite clay filmafter heat treatment at 250° C. The back reflection peaks 001 of the 10%caprolactam and 20% caprolactam were both observed at a position ofd=1.45 nm. These were spread out more than the 1.24 nm value of a claythin film (Kunipia P thin film), and correspond to structures in which anylon monomer and nylon are incorporated between layers ofmontmorillonite (Kunipia P). These results tell us that the nylonmonomer and nylon are present between layers of montmorillonite (KunipiaP), and are included in the clay layers. Meanwhile, the back reflectionpeak 001 of the 30% caprolactam was observed at d=129 nm, and it can beseen that the peak is wide. This indicates that the orientation of theclay particles in the composite film is somewhat lower than in the othersamples.

EXAMPLE 18

60 cc of distilled water was added to 0.95 g of synthetic saponite (asthe clay; Smectone, made by Kunimine Industries), and this was put intoa sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.05 g of epsilon-caprolactam powder (made by Wako Pure ChemicalIndustries), and this dispersion was poured into a flat-bottomed brasstray that had a circular bottom measuring about 15 cm in diameter, andthe dispersion was allowed to stand horizontally so that the clayparticles would gradually settle. With the tray held horizontal, thedispersion was dried for 5 hours at a temperature of 50° C. in a forcedair oven, which gave a semi-transparent, circular clay thin film with athickness of approximately 30 μm. Observation by electron microscoperevealed that the metal sheet and the clay thin film interfaces were incontact, with no gap in between, so the film did not peel away whenmerely touched by hand.

EXAMPLE 19

60 cc of distilled water was added to 1 g of natural montmorillonite (asthe clay; Kunipia P, made by Kunimine Industries), and this was put intoa sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 1 cc of an aqueous solution containing a specific proportion ofsodium polyacrylate (as a water-soluble polymer; made by Wako PureChemical Industries, degree of polymerization 2700 to 7500), which gavea dispersion containing natural montmorillonite and sodium polyacrylate.The specific proportion here was varied to produce dispersions withdifferent weight proportions of natural montmorillonite and sodiumpolyacrylate. The weight ratio of natural montmorillonite to sodiumpolyacrylate ranged from 0.90 g/0.2 g (2% sodium polyacrylate) to 1.00g/0.0000002 g (0.00002% sodium polyacrylate). Next, each dispersioncontaining natural montmorillonite and sodium polyacrylate was pouredinto a flat-bottomed brass tray that had a circular bottom measuringabout 15 cm in diameter, and the dispersion was allowed to standhorizontally so that the clay particles would gradually settle. With thetray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformwater-soluble polymer composite clay thin film with a. thickness ofapproximately 30 μm. The composite clay thin film thus produced waspeeled from the tray, which gave a water-soluble polymer composite claythin film that was self-supporting (self-standing) and had excellentflexibility. This film was also heat treated for 24 hours at 500° C.

FIG. 18 is an X-ray diffraction chart of a polyacrylate composite clayfilm (0.02% sodium polyacrylate) before heat treatment. A backreflection peak 001 was observed at d=1.23 nm in this X-ray diffractionchart. This peak is higher in intensity and narrower in width than thetypical back reflection peak of this type of clay mineral. It can beseen from these results that montmorillonite crystals are oriented inlayers in the composite clay thin films obtained using a polyacrylate.It can be seen that the back reflection peak intensity was particularlyhigh with the composite clay thin films obtained using sodiumpolyacrylate in an amount of from 0.005% to 0.1%, and that themontmorillonite crystals are highly oriented. Out of these compositeclay thin films, FIG. 19 is a TG-DTA chart (temperature elevation rate:5° C./minute, under an argon atmosphere) for the polyacrylate compositeclay thin film containing 0.02% sodium polyacrylate. The TG curve inFIG. 19 shows a reduction in weight caused by the dehydration ofadsorbed water from room temperature up to 200° C., and a large weightreduction in montmorillonite was observed from 700 to 800° C. No thermalchange or thermal weight change whatsoever could be observed in betweenthese temperatures. This indicates that a composite clay thin filmobtained using a polyacrylate exhibits high heat resistance.

The air permeation coefficients of composite clay thin films withdifferent proportions of polyacrylate were measured with a Gasperm-100made by JASCO. The weight ratios of the natural montmorillonite andsodium polyacrylate used in the preparation of the composite thin filmshere were 0.99 g/0.002 g (0.2% sodium polyacrylate), 1.00 g/0.0002 g(0.02% sodium polyacrylate), 1.00 g/0.00002 g(0.002% sodiumpolyacrylate), 1.00 g/0.000002 g (0.0002% sodium polyacrylate), and 1.00g/0.0000002 g (0.00002% sodium polyacrylate). The air permeationcoefficient at room temperature for all the composite thin films wasconfirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us thatthe films exhibit gas barrier performance. After these composite thinfilms were heated for 24 hours at 500° C., the air permeationcoefficient at room temperature was confirmed for all films to be lessthan 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us that the films exhibit gasbarrier performance even after high-temperature treatment.

EXAMPLE 20

60 cc of distilled water was added to 0.95 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.05 g of polyvinyl alcohol(as a water-soluble polymer; made by Kanto Chemical, degree ofpolymerization approximately 500). This dispersion containing naturalmontmorillonite and polyvinyl alcohol was poured into a flat-bottomedbrass tray that had a circular bottom measuring about 15 cm in diameter,and the dispersion was allowed to stand horizontally so that the clayparticles would gradually settle. With the tray held horizontal, thedispersion was dried for 5 hours at a temperature of 50° C. in a forcedair oven, which gave a uniform composite clay thin film with a thicknessof approximately 30 μm. The composite clay thin film thus produced wasthen peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyvinyl alcohol was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance. Also, the air permeation coefficient at room temperature ofthe film after heat treatment for 24 hours at 500° C. was confirmed tobe less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us that the filmexhibits gas barrier performance even after high-temperature treatment.

EXAMPLE 21

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of starch (as awater-soluble polymer; made by Nacalai Tesque). This dispersioncontaining natural montmorillonite and starch was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform composite clay thin filmwith a thickness of approximately 30 μm. The composite clay thin filmthus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using starch was measured with a Gasperm-100 made byJASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells usthat the film exhibits gas barrier performance.

EXAMPLE 22

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of hydroxyethylcellulose (as a water-soluble polymer; made by Aldrich ChemicalCompany). This dispersion containing natural montmorillonite andhydroxyethyl cellulose was poured into a flat-bottomed brass tray thathad a circular bottom measuring about 15 cm in diameter, and thedispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the tray held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a uniform composite clay thin film with a thickness ofapproximately 30 μm. The composite clay thin film thus produced was thenpeeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using hydroxyethyl cellulose was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 23

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of gelatin (as awater-soluble polymer; made by Wako Pure Chemical Industries). Thisdispersion containing natural montmorillonite and gelatin was pouredinto a flat-bottomed brass tray that had a circular bottom measuringabout 15 cm in diameter, and the dispersion was allowed to standhorizontally so that the clay particles would gradually settle. With thetray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm. Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using gelatin was measured with a Gasperm-100 made byJASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells usthat the film exhibits gas barrier performance.

EXAMPLE 24

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion was0.01 g of gluten (as a water-soluble polymer; made by Wako Pure ChemicalIndustries). This dispersion containing natural montmorillonite andgluten was poured into a flat-bottomed brass tray that had a circularbottom measuring about 15 cm in diameter, and the dispersion was allowedto stand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm. Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using gluten was measured with a Gasperm-100 made byJASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells usthat the film exhibits gas barrier performance.

EXAMPLE 25

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of polyethyleneglycol (as a water-soluble polymer; made by Tokyo Kasei Kogyo). Thisdispersion containing natural montmorillonite and polyethylene glycolwas poured into a flat-bottomed brass tray that had a circular bottommeasuring about 15 cm in diameter, and the dispersion was allowed tostand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm. Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyethylene glycol was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 26

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of polyacrylamide(as a water-soluble polymer; made by Aldrich Chemical Company). Thisdispersion containing natural montmorillonite and polyacrylamide waspoured into a flat-bottomed brass tray that had a circular bottommeasuring about 15 cm in diameter, and the dispersion was allowed tostand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm. Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyacrylamide was measured with a Gasperm-100made by JASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, whichtells us that the film exhibits gas barrier performance.

EXAMPLE 27

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of polyethyleneoxide (as a water-soluble polymer; made by Aldrich Chemical Company).This dispersion containing natural montmorillonite and polyethyleneoxide was poured into a flat-bottomed brass tray that had a circularbottom measuring about 15 cm in diameter, and the dispersion was allowedto stand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm.Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyethylene oxide was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 28

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 0.01 g of a powder of deoxyribonucleic acid (as a water-solublepolymer; made by Tokyo Kasei Kogyo). This dispersion containing naturalmontmorillonite and deoxyribonucleic acid was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform composite clay thin filmwith a thickness of approximately 30 μm. The composite clay thin filmthus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using deoxyribonucleic acid was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 29

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 0.01 g of a powder of poly-L-lysine hydrobromide (as awater-soluble polymer; made by ICN Biochemicals). This dispersioncontaining natural montmorillonite and poly-L-lysine hydrobromide waspoured into a flat-bottomed brass tray that had a circular bottommeasuring about 15 cm in diameter, and the dispersion was allowed tostand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm.Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using poly-L-lysine hydrobromide was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 30

60 cc of distilled water was added to 1.0 g of Kunipia P (as the clay; anatural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. This dispersion was pouredinto a flat-bottomed polypropylene tray that had a square bottommeasuring about 10 cm on each side. With the tray held horizontal, thedispersion was dried for 5 hours at a temperature of 50° C. in a forcedair oven, which gave a semi-transparent thin film with a thickness ofapproximately 40 μm. This film was then heat treated for 24 hours at1000° C.

In differential thermal analysis (temperature elevation rate: 5°C./minute) of this clay thin film, the weight reduction over atemperature range of 200° C. to 600° C. was 3.7%, and the fact that thisweight reduction was so small tells us that the basic structure of theclay constituting a gas blocking material is not affected by heating upto 600° C.

The air permeation coefficient of the thin film was measured with aGasperm-100 made by JASCO. As a result, the permeation coefficients forair, oxygen gas, nitrogen gas, hydrogen gas, and helium gas at roomtemperature were all confirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹,which tells us that the film exhibits gas barrier performance. Moleculesof helium gas are smaller than those of any other gas, and since thisthin film has high gas barrier performance against helium gas, it isbelieved that this thin film will exhibit high gas barrier performanceagainst all gases, regardless of the type. Also, the air permeationcoefficient of a thin film that had been heat treated for 24 hours at1000° C. was measured and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹,meaning that heat treatment was not observed to reduce gas barrierperformance.

Next, the water permeation coefficient of this thin film was measured toconfirm its water blocking performance. The water permeation coefficientwas measured using a type D universal water permeation coefficientmeasurement apparatus made by Hojun. As a result, the water permeationcoefficient of this thin film was found to be 1×10⁻¹¹ cm/sec, whichmeans that the film exhibits water blocking performance.

60 cc of distilled water was added to 1 g of natural montmorillonite (asthe clay; Kunipia P, made by Kunimine Industries), and this was put intoa sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 1 cc of an aqueous solution containing a specific proportion ofsodium polyacrylate (as a water-soluble polymer; made by Wako PureChemical Industries, degree of polymerization 2700 to 7500), which gavea dispersion containing natural montmorillonite and sodium polyacrylate.The specific proportion here was varied to produce dispersions withdifferent weight proportions of natural montmorillonite and sodiumpolyacrylate. The weight ratio of natural montmorillonite to sodiumpolyacrylate ranged from 0.98 g/0.02 g (2% sodium polyacrylate) to 1.00g/0.0000002 g (0.00002% sodium polyacrylate). Next, each dispersioncontaining natural montmorillonite and sodium polyacrylate was pouredinto a flat-bottomed brass tray that had a circular bottom measuringabout 15 cm in diameter, and the dispersion was allowed to standhorizontally so that the clay particles would gradually settle. With thetray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformwater-soluble polymer composite clay thin film with a thickness ofapproximately 30 μm. The composite clay thin film thus produced waspeeled from the tray, which gave a water-soluble polymer composite claythin film that was self-supporting and had excellent flexibility. Thisfilm was also heat treated for 24 hours at 500° C.

In differential thermal analysis (temperature elevation rate: 5°C./minute) of this sodium polyacrylate composite clay thin film, theweight reduction over a temperature range of 200° C. to 600° C. was3.3%, and the fact that this weight reduction was so small tells us thatthe basic structure of the clay constituting a gas blocking material isnot affected by heating up to 600° C. FIG. 20 is an X-ray diffractionchart of a polyacrylate composite clay thin film (0.02% sodiumpolyacrylate) prior to heat treatment. A back reflection peak 001 wasobserved at d=1.23 nm in this X-ray diffraction chart. This peak ishigher in intensity and narrower in width than the typical backreflection peak of this type of clay mineral. It can be seen from theseresults that montmorillonite crystals are oriented in layers in thecomposite clay thin films obtained using a polyacrylate. It can be seenthat the back reflection peak intensity was particularly high with thecomposite clay thin films obtained using sodium polyacrylate in anamount of from 0.005% to 0.1%, and that the montmorillonite crystals arehighly oriented. Out of these composite clay thin films, FIG. 21 is aTG-DTA chart (temperature elevation rate: 5° C./minute, under an argonatmosphere) for the polyacrylate composite clay thin film containing0.02% sodium polyacrylate. The TG curve in FIG. 21 shows a reduction inweight caused by the dehydration of adsorbed water from room temperatureup to 200° C., and a large weight reduction in montmorillonite wasobserved from 700 to 800° C. No thermal change or thermal weight changewhatsoever could be observed in between these temperatures. Thisindicates that a composite clay thin film obtained using a polyacrylateexhibits high heat resistance.

The air permeation coefficients of composite clay thin films withdifferent proportions of polyacrylate were measured with a Gasperm-100made by JASCO. The weight ratios of the natural montmorillonite andsodium polyacrylate used in the preparation of the composite thin filmshere were 0.99 g/0.002 g (0.2% sodium polyacrylate), 1.00 g/0.0002 g(0.02% sodium polyacrylate), 1.00 g/0.00002 g(0.002% sodiumpolyacrylate), 1.00 g/0.000002 g (0.0002% sodium polyacrylate), and 1.00g/0.0000002 g (0.00002% sodium polyacrylate). The air permeationcoefficient at room temperature for all the composite thin films wasconfirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us thatthe films exhibit gas barrier performance. After these composite thinfilms were heated for 24 hours at 500° C., the air permeationcoefficient at room temperature was confirmed for all films to be lessthan 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us that the films exhibit gasbarrier performance even after high-temperature treatment.

EXAMPLE 31

60 cc of distilled water was added to 0.95 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded 0.05 g of epsilon-caprolactam powder (as a nylon monomer; made byWako Pure Chemical Industries), and this dispersion was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform nylon monomer compositeclay thin film with a thickness of approximately 30 μm. The clay thinfilm thus produced was peeled from the tray and heat treated for 5 hoursin a heating oven held at 250° C., which gave a nylon composite clayfilm.

In differential thermal analysis (temperature elevation rate: 5°C./minute) of this nylon composite clay thin film, the weight reductionover a temperature range of 200° C. to 600° C. was 2.6%, and the factthat this weight reduction was so small tells us that the basicstructure of the clay constituting a gas blocking material is notaffected by heating up to 600° C.

The air permeation coefficient of the nylon composite clay film (theweight ratio of nylon monomer to total solids was 5%) was measured witha Gasperm-100 made by JASCO and confirmed to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, at room temperature, which tells us that the film exhibitsgas barrier performance. The air permeation coefficient of the filmafter heat treatment for 24 hours at 500° C. was confirmed to be lessthan 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, at room temperature, which tells us thatthe film exhibits gas barrier performance even after high-temperaturetreatment.

EXAMPLE 32

60 cc of distilled water was added to 0.95 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.05 g of polyvinyl alcohol(as a water-soluble polymer; made by Kanto Chemical, degree ofpolymerization approximately 500). This dispersion containing naturalmontmorillonite and polyvinyl alcohol was poured into a flat-bottomedbrass tray that had a circular bottom measuring about 15 cm in diameter,and the dispersion was allowed to stand horizontally so that the clayparticles would gradually settle. With the tray held horizontal, thedispersion was dried for 5 hours at a temperature of 50° C. in a forcedair oven, which gave a uniform composite clay thin film with a thicknessof approximately 30 μm. The composite clay thin film thus produced wasthen peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyvinyl alcohol was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance. Also, the air permeation coefficient at room temperature ofthe film after heat treatment for 24 hours at 500° C. was confirmed tobe less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us that the filmexhibits gas barrier performance even after high-temperature treatment.

EXAMPLE 33

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of starch (as awater-soluble polymer; made by Nacalai Tesque). This dispersioncontaining natural montmorillonite and starch was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform composite clay thin filmwith a thickness of approximately 30 μm. The composite clay thin filmthus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using starch was measured with a Gasperm-100 made byJASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells usthat the film exhibits gas barrier performance.

EXAMPLE 34

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of hydroxyethylcellulose (as a water-soluble polymer; made by Aldrich ChemicalCompany). This dispersion containing natural montmorillonite andhydroxyethyl cellulose was poured into a flat-bottomed brass tray thathad a circular bottom measuring about 15 cm in diameter, and thedispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the tray held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a uniform composite clay thin film with a thickness ofapproximately 30 μm. The composite clay thin film thus produced was thenpeeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using hydroxyethyl cellulose was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 35

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of gelatin (as awater-soluble polymer; made by Wako Pure Chemical Industries). Thisdispersion containing natural montmorillonite and gelatin was pouredinto a flat-bottomed brass tray that had a circular bottom measuringabout 15 cm in diameter, and the dispersion was allowed to standhorizontally so that the clay particles would gradually settle. With thetray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm. Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using gelatin was measured with a Gasperm-100 made byJASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells usthat the film exhibits gas barrier performance.

EXAMPLE 36

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of gluten (as awater-soluble polymer; made by Wako Pure Chemical Industries). Thisdispersion containing natural montmorillonite and gluten was poured intoa flat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform composite clay thin filmwith a thickness of approximately 30 μm. The composite clay thin filmthus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using gluten was measured with a Gasperm-100 made byJASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells usthat the film exhibits gas

EXAMPLE 37

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of polyethyleneglycol (as a water-soluble polymer; made by Tokyo Kasei Kogyo). Thisdispersion containing natural montmorillonite and polyethylene glycolwas poured into a flat-bottomed brass tray that had a circular bottommeasuring about 15 cm in diameter, and the dispersion was allowed tostand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm.Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyethylene glycol was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 38

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of polyacrylamide(as a water-soluble polymer; made by Aldrich Chemical Company). Thisdispersion containing natural montmorillonite and polyacrylamide waspoured into a flat-bottomed brass tray that had a circular bottommeasuring about 15 cm in diameter, and the dispersion was allowed tostand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30. μm.Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyacrylamide was measured with a Gasperm-100made by JASCO and found to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, whichtells us that the film exhibits gas barrier performance.

EXAMPLE 39

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 1 cc of an aqueous solution containing 0.01 g of polyethyleneoxide (as a water-soluble polymer; made by Aldrich Chemical Company).This dispersion containing natural montmorillonite and polyethyleneoxide was poured into a flat-bottomed brass tray that had a circularbottom measuring about 15 cm in diameter, and the dispersion was allowedto stand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm.Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using polyethylene oxide was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 40

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 0.01 g of a powder of deoxyribonucleic acid (as a water-solublepolymer; made by Tokyo Kasei Kogyo). This dispersion containing naturalmontmorillonite and deoxyribonucleic acid was poured into aflat-bottomed brass tray that had a circular bottom measuring about 15cm in diameter, and the dispersion was allowed to stand horizontally sothat the clay particles would gradually settle. With the tray heldhorizontal, the dispersion was dried for 5 hours at a temperature of 50°C. in a forced air oven, which gave a uniform composite clay thin filmwith a thickness of approximately 30 μm. The composite clay thin filmthus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using deoxyribonucleic acid was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 41

60 cc of distilled water was added to 0.99 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. Into this dispersion wasmixed 0.01 g of a powder of poly-L-lysine hydrobromide (as awater-soluble polymer; made by ICN Biochemicals). This dispersioncontaining natural montmorillonite and poly-L-lysine hydrobromide waspoured into a flat-bottomed brass tray that had a circular bottommeasuring about 15 cm in diameter, and the dispersion was allowed tostand horizontally so that the clay particles would gradually settle.With the tray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave a uniformcomposite clay thin film with a thickness of approximately 30 μm.Thecomposite clay thin film thus produced was then peeled from the tray.

The air permeation coefficient at room temperature of the composite claythin film obtained using poly-L-lysine hydrobromide was measured with aGasperm-100 made by JASCO and found to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 42

60 cc of distilled water was added to 0.95 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded an aqueous solution containing 0.05 g of epsilon-caprolactam (as awater-soluble polymer; made by Wako Pure Chemical Industries), and thisdispersion was poured into a flat-bottomed brass tray that had acircular bottom measuring about 15 cm in diameter, and the dispersionwas allowed to stand horizontally so that the clay particles wouldgradually settle. With the tray held horizontal, the dispersion wasdried for 5 hours at a temperature of 50° C. in a forced air oven, whichgave a uniform composite clay thin film with a thickness ofapproximately 30 μm.The clay thin film thus produced was peeled from thetray to obtain a composite clay film.

The composite clay film thus obtained was cut to a length of 10 cm and awidth of 2 cm, and wrapped around the thread components (N30, P2) of theautoclave (made of SUS 316, internal volume of 30 cc) shown in FIG. 22.Next, 20 cc of distilled water was put into the autoclave, and theinserted part was fastened by screwing down the lid with a wrench. Thisautoclave was then placed in an electric furnace held at 300° C., thechange in the weight of the autoclave over time was measured, and theremainder ratio versus the initial value for water was calculated fromthis change. FIG. 23 shows the relationship between elapsed time and thewater remainder ratio. When the composite clay film was wrapped aroundthe threads, the water content remained unchanged for 72 hours, andbarrier performance against high-temperature and high-pressure steam wasexhibited.

Comparative Example 2

20 cc of distilled water was put into the autoclave (made of SUS 316,internal volume of 30 cc) shown in FIG. 22, and the inserted part wasfastened by screwing down the lid with a wrench. This autoclave was thenplaced in an electric furnace held at 300° C., the change in the weightof the autoclave over time was measured, and the remainder ratio versusthe initial value for water was calculated from this change. FIG. 23shows the relationship between elapsed time and the water remainderratio. All of the water in the autoclave had been lost after 45 minutes.

EXAMPLE 43

60 cc of distilled water was added to 0.32 g of natural montmorillonite(as the clay; Kunipia P, made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. To this dispersion wasadded an aqueous solution containing 0.017 g of epsilon-caprolactam (asa water-soluble polymer; made by Wako Pure Chemical Industries), andthis dispersion was poured into a flat-bottomed brass tray that had acircular bottom measuring about 15 cm in diameter, and the dispersionwas allowed to stand horizontally so that the clay particles wouldgradually settle. With the tray held horizontal, the dispersion wasdried for 5 hours at a temperature of 50° C. in a forced air oven, whichgave a uniform composite clay thin film with a thickness ofapproximately 10 μm.The clay thin film thus produced was peeled from thetray to obtain a composite clay film.

The composite clay film thus obtained was cut to a suitable size,sandwiched between two plastic films as shown in FIG. 24, and thesefilms were bonded together with an adhesive to produce a three-layerfilm. The plastic films were made of a fluororesin(tetrafluoroethylene), and the thickness of one layer was 50 μm. Thehelium permeation coefficient of this multilayer film was measured witha Gasperm-100 made by JASCO and confirmed to be less than 5.9×10⁻¹¹cm²s⁻¹cmHg⁻¹ at room temperature, which tells us that the multilayerfilm exhibits gas barrier performance.

Comparative Example 3

As shown in FIG. 25, two plastic films were bonded together with anadhesive to produce a two-layer film. The plastic films were made of afluororesin (tetrafluoroethylene), and the thickness of one layer was 50μm. The helium permeation coefficient of this multilayer film wasmeasured with a Gasperm-100 made by JASCO and confirmed to be1.1×10^(−19 cm) ²s⁻¹cmHg⁻¹ at room temperature.

EXAMPLE 44

60 cc of distilled water was added to 0.95 g of Smectone (as the clay; asynthetic saponite made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. This dispersion was pouredinto a flat-bottomed brass tray that had a circular bottom measuringabout 15 cm in diameter, and the dispersion was allowed to standhorizontally so that the clay particles would gradually settle. With thetray held horizontal, the dispersion was dried for 5 hours at atemperature of 50° C. in a forced air oven, which gave asemi-transparent, circular clay thin film with a thickness ofapproximately 30 μm. Observation by electron microscope revealed thatthe metal sheet and the clay thin film interfaces were in contact, withno gap in between, so the film did not peel away when merely touched byhand.

EXAMPLE 45

60 cc of distilled water was added to 1.0 g of Kunipia P (as the clay; anatural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform clay dispersion. This clay dispersionwas poured onto a flat-bottomed stainless steel support that had asquare bottom measuring about 10 cm on each side, and the claydispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the support held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent clay thin film/support with a thickness ofapproximately 40 μm.

FIG. 26 shows a scanning electron micrograph of this clay thin film. Itcan be seen in FIG. 26 how highly oriented the clay particles are. FIG.27 is an X-ray diffraction chart of this clay thin film. A series ofsharp back reflection peaks (001), (002), (003), (004), and (005) areseen at positions of 1.24, 0.62, 0.42, 0.31, and 0.21 nm, respectively,indicating that the orientation of the particles in the clay thin filmis very uniform.

EXAMPLE 46

60 cc of distilled water was added to magnesium Kunipia P (as the clay),obtained by exchanging the exchangeable ions of 1.0 g of naturalmontmorillonite (Kunipia P made by Kunimine Industries) with magnesium,and this was put into a sealed plastic vessel along with a Teflon®agitator and shaken vigorously, which gave a uniform clay dispersion.This clay dispersion was poured onto a flat-bottomed stainless steelsupport that had a square bottom measuring about 10 cm on each side, andthe clay dispersion was allowed to stand horizontally so that the clayparticles would gradually settle. With the support held horizontal, thedispersion was dried for 5 hours at a temperature of 50° C. in a forcedair oven, which gave a semi-transparent clay thin film/support with athickness of approximately 70 μm.

EXAMPLE 47

60 cc of distilled water was added to 1.0 g of Smectone (as the clay; asynthetic saponite made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform clay dispersion. This clay dispersionwas poured onto a flat-bottomed stainless steel support that had asquare bottom measuring about 10 cm on each side, and the claydispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the support held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent clay thin film/support with a thickness ofapproximately 70 μm. The water permeation coefficient of this clay thinfilm was measured and found to be 2=10⁻¹⁰ cm/sec, meaning that goodwater blocking was exhibited.

EXAMPLE 48

60 cc of distilled water was added to 1.0 g of Kunipia P (as the clay; anatural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform clay dispersion. This clay dispersionwas poured into a flat-bottomed brass support that had a circular bottommeasuring about 15 cm in diameter, and the dispersion was allowed tostand horizontally so that the clay particles would gradually settle.With the support held horizontal, the dispersion was dried for 5 hoursat a temperature of 50° C. in a forced air oven, which gave asemi-transparent, circular clay thin film/support with a thickness ofapproximately 70 μm.

The helium, hydrogen, oxygen, nitrogen, and air permeation coefficientsof this film were measured with a Gasperm-100 made by JASCO. The gaspermeation coefficients for helium, hydrogen, oxygen, nitrogen, and airat room temperature were confirmed to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance. Even after this composite thin film was heated for 24 hoursat 1000° C, the gas permeation coefficients of the composite thin filmfor helium, hydrogen, oxygen, nitrogen, and air at room temperature wereconfirmed to be less than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us thatthe film exhibits gas barrier performance even after high-temperaturetreatment. The optical transmissivity of this film was measured with aU-3310 absorptiometer made by Hitachi. The optical transmissivity wasmeasured by immersing the film in ethanol in a quartz rectangular celland using light with a wavelength of 500 nm. As a result, the opticaltransmissivity was found to be 75%.

EXAMPLE 49

60 cc of distilled water was added to 0.95 g of Smectone (as the clay; asynthetic saponite made by Kunimine Industries), and this was put into asealed plastic vessel along with a Teflon® agitator and shakenvigorously, which gave a uniform dispersion. This dispersion was pouredonto a flat-bottomed support in the form of a metal (brass) sheet thathad a circular bottom measuring about 15 cm in diameter, and thedispersion was allowed to stand horizontally so that the clay particleswould gradually settle. With the support held horizontal, the dispersionwas dried for 5 hours at a temperature of 50° C. in a forced air oven,which gave a semi-transparent, circular clay thin film/support with athickness of approximately 30 μm. Observation by electron microscoperevealed that the metal sheet and the clay thin film interfaces were incontact, with no gap in between, so the film did not peel away whenmerely touched by hand.

EXAMPLE 50

60 cc of distilled water was added to 1.0 g of Kunipia P (as the clay; anatural montmorillonite made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously for 30 minutes at 25° C., which gave a uniform dispersion.This dispersion was gradually dried at a temperature of 50° C., whichgave a clay paste with a solid/liquid ratio of about 6 wt %. A brasstray was then coated with this clay paste. A stainless steel spreaderblade was used for this coating. A spacer was used as a guide to form aclay paste film of uniform thickness. The thickness of the paste herewas 0.3 mm.

This tray was put in a forced air oven and the film was dried for 20minutes at a temperature of 50° C., which gave a semi-transparent,uniform, additive-containing composite clay thin .film with a thicknessof approximately 10 μm. The clay film thus produced was peeled from thetray, which gave a self-supporting clay film with excellent flexibility.The air permeation coefficient of this clay film was measured with aGasperm-100 made by JASCO. As a result, the air permeation coefficientat room temperature was confirmed to be less than 3.2×10⁻¹¹cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gas barrierperformance.

EXAMPLE 51

60 cc of distilled water was added to 0.90 g of natural montmorillonite(as the clay; Kunipia P made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously for 30 minutes at 25° C., which gave a uniform dispersion. Tothis dispersion was added 0.10 g of epsilon-caprolactam (as an additive;made by Wako Pure Chemical Industries), which gave a dispersioncontaining natural montmorillonite and epsilon-caprolactam. Next, thedispersion containing natural montmorillonite and epsilon-caprolactamwas gradually dried at a temperature of 50° C., which gave a clay pastewith a solid/liquid ratio of about 6 wt %. A brass tray was then coatedwith this clay paste. A stainless steel spreader blade was used for thiscoating. A spacer was used as a guide to form a clay paste film ofuniform thickness. The thickness of the paste here was 0.06 mm. Thistray was put in a forced air oven and the film was dried for 20 minutesat a temperature of 50° C., which gave a semi-transparent, uniform,additive-containing composite clay thin film with a thickness ofapproximately 2 μm. The clay film thus produced was peeled from thetray, which gave a self-supporting clay film with excellent flexibility.

EXAMPLE 52

60 cc of distilled water was added to 0.90 g of natural montmorillonite(as the clay; Kunipia P made by Kunimine Industries), and this was putinto a sealed plastic vessel along with a Teflon® agitator and shakenvigorously for 30 minutes at 25° C., which gave a uniform dispersion. Tothis dispersion was added 0.10 g of epsilon-caprolactam (as an additive;made by Wako Pure Chemical Industries), which gave a dispersioncontaining natural montmorillonite and epsilon-caprolactam. Next, thedispersion containing natural montmorillonite and epsilon-caprolactamwas gradually dried at a temperature of 50° C., which gave a clay pastewith a solid/liquid ratio of about 6 wt %.

A brass tray was then coated with this clay paste. A stainless steelspreader blade was used for this coating. A spacer was used as a guideto form a clay paste film of uniform thickness. The thickness of thepaste here was 0.3 mm. This tray was put in a forced air oven and thefilm was dried for 20 minutes at a temperature of 50° C., which gave asemi-transparent, uniform, additive-containing composite clay thin filmwith a thickness of approximately 10 μm. The clay film thus produced waspeeled from the tray, which gave a self-supporting clay film withexcellent flexibility. The air permeation coefficient of this clay filmwas measured with a Gasperm-100 made by JASCO. As a result, the airpermeation coefficient at room temperature was confirmed to be less than3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹, which tells us that the film exhibits gasbarrier performance.

Comparative Example 4

60 cc of distilled water was added to 1 g of natural montmorillonite (asthe clay; Kunipia P made by Kunimine Industries), and this was put intoa sealed plastic vessel along with a Teflon® agitator and shakenvigorously for 30 minutes at 25° C., which gave a uniform dispersion.This dispersion was poured into a flat-bottomed brass tray that had acircular bottom measuring about 15 cm in diameter, and the dispersionwas allowed to stand horizontally so that the clay particles wouldgradually settle. With the tray held horizontal, the dispersion wasdried for 5 hours at a temperature of 50° C. in a forced air oven, whichgave a uniform clay film with a thickness of approximately 30 μm. Theclay film thus produced was peeled from the tray, which gave aself-supporting clay film with excellent flexibility.

INDUSTRIAL APPLICABILITY

The present invention provides a novel clay film that can be used as aself-supporting film, has excellent flexibility, is a solid materialthat is free of pinholes, has excellent barrier properties, and isuseful as a chemical stable gasket material or the like that can be usedunder high temperature conditions over 350° C. The present inventionalso provides a film with the excellent heat resistance and barrierproperties of clay, resulting from the clay particles being highlyoriented. Because the clay film of the present invention can be used asa self-supporting film and has excellent heat resistance andflexibility, it can be used in a wide range of applications, such asfilters and diaphragms. The clay film of the present invention can alsobe used for pipe sealing materials that block off gases, solutions,oils, and so forth, fuel sealants used around rocket and jet engines,fuel cell diaphragms, and so on. Also, with the present invention, theabove-mentioned clay film can be manufactured by a simple process thatdoes not generate waste liquid. Also, after the solvent has been removedand the clay film formed, it can be used as a protective film for asupport, without first being peeled away from the support surface, andtherefore serves to prevent the corrosion and fouling of a support andincrease its heat resistance.

1. A clay film characterized in that the clay film is made up of a maincomponent of clay, or clay and a small amount of additive, or clay and asmall amount of additive and a functional component, having a structurein which layers of clay particles are highly oriented, having enoughmechanical strength and flexibility to be used as a self-supportingfilm, containing no pinholes, and having a gas permeation coefficient ofless than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹ at room temperature for helium,hydrogen, oxygen, nitrogen, or air.
 2. The clay film according to claim1, wherein the main constituent component of the clay film is naturalclay or synthetic clay.
 3. The clay film according to claim 1, whereinthe main constituent component of the clay film is one or morecomponents selected from the group comprising mica, vermiculite,montmorillonite, iron montmorillonite, beidellite, saponite, hectorite,stevensite, and nontronite.
 4. The clay film according to claim 1,wherein the additive is one or more types selected from the compoundgroup comprising epsilon-caprolactam, dextrin, chitosan, starch,cellulose resin, gelatin, agar-agar, wheat flour, gluten, alkyd resin,polyurethane resin, epoxy resin, fluororesin, acrylic resin, methacrylicresin, phenol resin, polyamide resin, polyester resin, polyimide resin,polyvinyl resin, polyethylene glycol, polyacrylamide, polyethyleneoxide, protein, deoxyribonucleic acid, ribonucleic acid, polyamino acid,phenols, and benzoic acids.
 5. The clay film according to claim 1,wherein the functional component is an enzyme, polyhydric phenol, ornylon.
 6. The clay film according to claim 4, wherein the phenol is oneor more types from among hydroquinone, resorcin, pyrocatechol, andphloroglucin.
 7. The clay film according to claim 1, which has anytwo-dimensional planar shape, typified by circular, square, orrectangular, or any three-dimensional planar shape that is a flat plate,tube, circular column, cone, sphere, or a combination thereof, and whichcan be used as a self-supporting film.
 8. The clay film according toclaim 1, wherein the thickness is less than 1 mm and the surface area isgreater than 1 cm².
 9. The clay film according to claim 1, wherein theweight proportion of the additive versus the total solids is not morethan 30%.
 10. The clay film according to claim 1, wherein the weightproportion of the functional component versus the total solids is notmore than 30%.
 11. The clay film according to claim 1, wherein theflexibility is excellent, the weight loss over a temperature range of200 to 600° C. in differential thermal analysis is less than 10%, thebasic structure does not change, and no pinholes exist.
 12. The clayfilm according to claim 1, wherein the weight proportion of the maincomponent clay versus the total solids is at least 90%.
 13. The clayfilm according to claim 1, wherein the gas permeation coefficient isless than 3.2×10⁻¹¹ cm²s⁻¹cmHg⁻¹ at room temperature for helium,hydrogen, oxygen, nitrogen, or air after 24 hours of heat treatment at600° C.
 14. The clay film according to claim 1, wherein the waterpermeation coefficient is not more than 2×10⁻¹⁰ cm s⁻¹ at roomtemperature.
 15. The clay film according to claim 1, wherein the gasbarrier property or the mechanical strength is improved by conducting achemical reaction such as an addition reaction, condensation reaction,or polymerization reaction by any method, such as heating or opticalirradiation, and producing new chemical bonds between the clay, theadditive, and the functional component, or within the components. 16.The clay film according to claim 1, wherein the transmissivity of lightwith a wavelength of 500 nm is at least 75%.
 17. A member with highbarrier properties, made from the clay film according to any of claims 1to
 16. 18. A protective film, made of the clay film according to any ofclaims 1 to
 16. 19. A gas blocking material, made from the clay filmaccording to any of claims 1 to 16.